I. Field of the Invention
The present invention relates generally to electrosurgical instruments, and more particularly to a bipolar electrosurgical device for coagulation and cutting of target tissue and specifically designed for use in the performance of percutaneous laparoscopic surgery such as laparoscopic cholecystectomy, or similar endoscopic procedures.
II. Background of the Invention
For a number of years, the medical device industry, in cooperation with health care providers, has been developing methods and devices to permit surgical procedures to be performed in a less invasive manner. Minimally invasive surgery (MIS) generally involves the use of instruments which avoid the need to make major incisions in the body. Such major incisions usually require a relatively long period of hospitalization and subsequent home recovery. Using laparoscopic procedures, gall bladder removal can now be performed routinely through a trocar cannula. Surgeons are also performing appendectomies and hysterectomies through a trocar cannula.
When these MIS procedures are performed laparoscopically, the cutting and coagulating instruments most often used are either electrosurgical or laser based. Although capable of more precise cutting than electrosurgical instruments, lasers are somewhat difficult to control, particularly in the closed conditions of laparoscopic procedure. Laser systems are also expensive to acquire and sometimes inconvenient for the physician due to the problems of scheduling the limited number of laser units which would tend to be available in a typical hospital and the high level of expertise required in operating the laser scalpel.
MIS procedures are typically performed using monopolar electrosurgical instruments, which have inherent characteristics that pose certain risks for patients. In electrosurgery, radio frequency (RF) energy is used both to cut and coagulate tissue. In monopolar devices, the RF energy must pass from the surgical area and the surgical instrument through the patient's body to separate electrodes attached to a large surface area, generally the buttocks or thigh. In monopolar electrosurgery, there is a greater potential for injury to body tissues as the electrical current passes through them to the surface or return electrode. Skin burns can also occur at the site of the return electrode. In laparoscopic procedures, there is even a greater potential for complications when using monopolar instruments, due to the combined effects of the surgeons limited field of vision, the proximity of other organs and the inherent tendency of surgical instruments to conduct monopolar RF energy.
Bipolar electrosurgical products provide an improved margin of patient safety in certain minimally invasive surgical and interventional procedures. In bipolar devices, the RF energy is contained at the surgical site because both the active and return electrodes are located on the surgical instrument itself.
As mentioned above, a common laparoscopic surgical procedure is a laparoscopic cholecystectomy. Laparoscopic surgery is performed through several openings in the body which are made using trocars inserted through very small punctures. In a first such puncture a rigid endoscope called a laparoscope is inserted through a trocar to give the surgeon a view of the operative area. An electrosurgical device is inserted through a different trocar to allow required cutting and coagulation. Other grasping instruments may also be used in manipulating the organ being excised as connective tissue is being cut.